High-energy photons, such as X-rays, for example, can pass through objects before being significantly absorbed. Hence, high-energy photons are widely used to form images in security, medical imaging and industrial applications. Unlike normal reflection images, 3D objects are projected onto 2D images and appear semi-transparent in such high-energy images. In dual-energy X-ray imaging, two images are acquired by X-rays with relatively high-energy and relatively low energy spectra, respectively.
Images consisting of transparent layers are rarely addressed by conventional computer vision techniques. The transparency observed in emerging X-ray imaging devices in security, medical imaging and industrial inspection poses great challenges to existing algorithms.
Ongoing research attempts to address transparency in stereo estimation, image registration and layer separation. What is currently needed is a system and method for separating moving transparent layers in a dual-energy X-ray imaging scenario.